15 ILCS 405/4

If any person elected to the office of comptroller, or appointed to fill a vacancy in that office, fails to give bond or to take the oath or affirmation required under Section 3 on or before the date fixed for commencement of his term, the office becomes vacant. If the comptroller, when required to give additional bond under Section 3, fails to do so within 20 days after notice of such requirement, the Governor may declare that office vacant and appoint a successor in the manner provided by law.